Virtual Sheep Genome

What is the difference between the virtual sheep genome and the real
sheep genome?

The virtual sheep genome is the sequence of the bovine genome reorganised
into the structure of the sheep genome based on syntenic blocks defined
using sheep BACs. In the real sheep genome the bovine sequence in the
virtual sheep genome is replaced with actual sheep sequence, or n's where
no sheep sequence is available.

Why have a virtual sheep genome when we have a real sheep genome sequence?

The real sheep genome sequence assembly covers approximately 43% of the
actual total genome sequence and as only information mappable by sequence
alignment is displayed many sheep markers, BAC-end sequences etc. are
not mappable and are not displayed. In contrast, the virtual sheep genome
contains markers, BAC-end sequences etc. mapped using comparative approaches
and therefore is much more comprehensive in it's coverage.

For maximum information about a region use the virtual sheep genome and
for real sheep sequence use the real sheep genome assembly. As both are
based on the same comparative framework the orders of features should be
the same and are heavily biased towards synteny with the cattle genome.
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Markers

The sheep marker data used to generate
the following items was provided courtesy of the
Australian Sheep Gene Mapping Web Site. The original
data coordinates were in cM. However, base-pair coordinates have been
approximated by multiplying each position by 1,000,000.